David, our favourite statistician, has guided us through many a sticky statistical situation and has met many of his own making, including an excellent round on Winter Wipeout. He wrote a column here at Plus and is responsible for the excellent website Understanding Uncertainty, as well as many other activities. Michael, journalist, author and radio producer, is the person who first introduced us to the world of radio and podcasting. He created the fabulous BBC Radio 4 show More or Less.

You can read more about the maths of networks on Plus, including the networks behind our brains, rapping, crime fighting and the best parties. And to find out how this all started, why not watch our oscar-worthy movie below!

Beck creates those beautiful geometrical shapes by walking through the snow. The shape you see above is based on the Von Koch snowflake. To create the full shape, you start with an equilateral triangle and replace the middle third of each side by a "spike" consisting of two sides of a smaller equilateral triangle. Now do the same for each of the twelve straight-line segments of the resulting shape and repeat, ad infinitum. The Von Koch snowflake is an example of a fractal, a mathematical shape that is infinitely intricate and self-similar: it exhibits the same structures over and over again as you zoom in on smaller and smaller pieces. You can find out more about fractals here.

Beck can't produce the Von Koch snowflake exactly, of course, because it involves an infinite process. But he has created an amazingly good approximation, which comes from using the first few iterations of the process. He gets the shape down in the snow by counting steps to measure distances and using a compass when changing direction to make sure he gets the correct angles between straight-line segments. "In the case of the Koch shape, I found I was soon able to judge the 60 degree angles and do it quicker to an acceptable level of accuracy without using the compass," he says.

If you like the pictures, you can see more of them in Beck's new book, Snow Art, which you can purchase from his website. Here are a few more samples:

An image taken by the Hubble Space Telescope, courtesy NASA, ESA and E. Sabbi (ESA/STScI).

How important are experiments in science? Scientists use experiments
to check whether a theory's predictions match up with
reality, so without them you can't pick out bad theories.

In
theoretical physics, however, there are many theories that cannot be
tested. Not only because our experimental tools are nowhere near good
enough, but also because there's some fundamental reason that stops us
exploring some of the predictions those theories make. Examples are string theory, M theory and the various multiverse theories. Should we
pursue them anyway, or dismiss them as speculation?

This debate, featuring one of our favourite theoretical physicists, David Tong (among others), explores this question and asks whether physics has strayed too far from experiment. It's been produced by the Institute of Art and Ideas in London.

Our good friend Julian Gilbey has just told us about an amazing fact: if you roll a parabola along a straight line then the shape its focus traces out as it goes is ... a catenary! That's the shape a chain makes when it hangs freely under gravity and also the shape that gives you the strongest arches (see here and here to learn more).

Just why the two curves are connected in this way is a mystery (at least to us) — you can do the maths to prove it, but there doesn't seem an intuitive reason.

Julian has also produced this beautiful applet to illustrate the result. It shows the graph of the parabola with equation

which has its focus at the point (Use the left-hand slider to change the value of ) You can roll the parabola along using the right-hand slider and see the catenary the focus traces out. Its equation is

There are problems that are easy to solve in theory, but impossible to solve in practice. Intrigued? Then join us on a journey through the world of complexity, all the way to the famous P versus NP conjecture.